Battery voltage goes down

[hardheaded]

I disconnected the ground cable when i did the parasitic draw testing and it was 0.003 milliamps. I have been watching the battery in this cold weather and all seems well right now. I will drive the truck next week after all this salt is gone.

 

[jeffy876]

He did not say he disconnected the battery to test it. These vehicles will power up half the systems if you open a door and drop the voltage down that low or lower.

Shouldn't drop quite that much from opening a doors. Not from a full charge. Its within the realm of possibility if it's a really cold battery but I wouldn't say that's normal.

Btw, I do agree that this is a non-issue.

Open circuit voltage is a poor way to test any battery and does not give you an indication of health or a very accurate state of charge.

SoH yes, OCV doesn't tell you anything about battery health.
But for SoC, OCV works great. It's not going to tell you if you're at 100% or 90%, but it'll tell you if it's at 90% or 20% just fine.
But again, I agree this is a non-issue.

 

[jeffy876]

I disconnected the ground cable when i did the parasitic draw testing and it was 0.003 milliamps. I have been watching the battery in this cold weather and all seems well right now. I will drive the truck next week after all this salt is gone.

You mean 0.003 amps i think

 

[hardheaded]

You mean 0.003 amps i think

Yes that it what i meant.

 

[zzyzzx]

If you're measuring the voltage with the ignition on, 11.7 V isn't abnormal if the battery is really cold. Even opening the car doors or using the key fob can put load on the battery and drop the voltage for a while. So can having the hood open if your car has a hood sensor. Be sure you're checking the voltage while the battery is at rest.

I saw mine at 11.2 on a cold morning recently. Car started just fine, even with a V6.